http://www.7-zip.org/sdk.html 这个站点提供了一个用于压缩/解压缩文件的LZMA SDK，我想试一试，但我迷路了。
有人有这方面的经验吗？还是教程？感谢。
答案 0 :(得分：38)
简答：不要
7zip sdk是旧的，没有维护，它只是一个围绕C ++库的JNI包装器。现代JVM（1.7 +）上的纯Java实现与C ++实现一样快，并且具有较少的依赖性和可移植性问题。
查看http://tukaani.org/xz/java.html
XZ是基于LZMA2（LZMA的改进版本）的文件格式
发明XZ格式的人构建了XZ归档压缩/提取算法的纯java实现
XZ文件格式仅用于存储1个文件。因此，您需要先将源文件夹压缩/ tar到一个未压缩的文件中。
使用java库就像这样简单：
FileInputStream inFile = new FileInputStream("src.tar");
FileOutputStream outfile = new FileOutputStream("src.tar.xz");
LZMA2Options options = new LZMA2Options();
options.setPreset(7); // play with this number: 6 is default but 7 works better for mid sized archives ( > 8mb)
XZOutputStream out = new XZOutputStream(outfile, options);
byte[] buf = new byte[8192];
int size;
while ((size = inFile.read(buf)) != -1)
out.write(buf, 0, size);
out.finish();
答案 1 :(得分：4)
从您发布的链接中查看zip文件的Java / SevenZip文件夹中的LzmaAlone.java和LzmaBench.java文件。
答案 2 :(得分：3)
使用J7Zip。它是LZMA SDK的java端口。你在这里找到它：
http://sourceforge.net/projects/p7zip/files/J7Zip/
替代
将lzmajio.jar与LzmaInputStream和LzmaOutputStream类一起使用
你在github上找到它：
答案 3 :(得分：2)
您可以使用this库。它“过时”但仍然可以正常工作。
Maven依赖
<dependency>
<groupId>com.github.jponge</groupId>
<artifactId>lzma-java</artifactId>
<version>1.2</version>
</dependency>
公用事业类
import lzma.sdk.lzma.Decoder;
import lzma.streams.LzmaInputStream;
import lzma.streams.LzmaOutputStream;
import org.apache.commons.compress.utils.IOUtils;
import java.io.*;
import java.nio.file.Path;
public class LzmaCompressor
{
private Path rawFilePath;
private Path compressedFilePath;
public LzmaCompressor(Path rawFilePath, Path compressedFilePath)
{
this.rawFilePath = rawFilePath;
this.compressedFilePath = compressedFilePath;
}
public void compress() throws IOException
{
try (LzmaOutputStream outputStream = new LzmaOutputStream.Builder(
new BufferedOutputStream(new FileOutputStream(compressedFilePath.toFile())))
.useMaximalDictionarySize()
.useMaximalFastBytes()
.build();
InputStream inputStream = new BufferedInputStream(new FileInputStream(rawFilePath.toFile())))
{
IOUtils.copy(inputStream, outputStream);
}
}
public void decompress() throws IOException
{
try (LzmaInputStream inputStream = new LzmaInputStream(
new BufferedInputStream(new FileInputStream(compressedFilePath.toFile())),
new Decoder());
OutputStream outputStream = new BufferedOutputStream(
new FileOutputStream(rawFilePath.toFile())))
{
IOUtils.copy(inputStream, outputStream);
}
}
}
首先，您必须创建一个包含内容的文件以开始压缩。您可以使用this网站生成随机文字。
压缩和解压缩示例
Path rawFile = Paths.get("raw.txt");
Path compressedFile = Paths.get("compressed.lzma");
LzmaCompressor lzmaCompressor = new LzmaCompressor(rawFile, compressedFile);
lzmaCompressor.compress();
lzmaCompressor.decompress();
答案 4 :(得分：0)
以下是使用XZ Utils纯java库以LZMA2压缩算法打包和解压缩XZ压缩文件的测试示例。
import org.tukaani.xz.*;
// CompressXz
public static void main(String[] args) throws Exception {
String from = args[0];
String to = args[1];
try (FileOutputStream fileStream = new FileOutputStream(to);
XZOutputStream xzStream = new XZOutputStream(
fileStream, new LZMA2Options(LZMA2Options.PRESET_MAX), BasicArrayCache.getInstance())) {
Files.copy(Paths.get(from), xzStream);
}
}
// DecompressXz
public static void main(String[] args) throws Exception {
String from = args[0];
String to = args[1];
try (FileInputStream fileStream = new FileInputStream(from);
XZInputStream xzStream = new XZInputStream(fileStream, BasicArrayCache.getInstance())) {
Files.copy(xzStream, Paths.get(to), StandardCopyOption.REPLACE_EXISTING);
}
}
// DecompressXzSeekable (partial)
public static void main(String[] args) throws Exception {
String from = args[0];
String to = args[1];
int offset = Integer.parseInt(args[2]);
int size = Integer.parseInt(args[3]);
try (SeekableInputStream fileStream = new SeekableFileInputStream(from);
SeekableXZInputStream xzStream = new SeekableXZInputStream(fileStream, BasicArrayCache.getInstance())) {
xzStream.seek(offset);
byte[] buf = new byte[size];
if (size != xzStream.read(buf)) {
xzStream.available(); // let it throw the last exception, if any
throw new IOException("Truncated stream");
}
Files.write(Paths.get(to), buf);
}
}
答案 5 :(得分：0)
https://mvnrepository.com/artifact/org.tukaani/xz/1.8
Android的Kotlin代码：
fun initDatabase() {
var gisFile = this.getDatabasePath("china_gis.db");
if (!gisFile.exists()) {
if(!gisFile.parentFile.exists()) gisFile.parentFile.mkdirs();
var inStream = assets.open("china_gis_no_poly.db.xz")
inStream.use { input ->
val buf = ByteArray(1024)
XZInputStream(input).use { input ->
FileOutputStream(gisFile,true).use { output ->
var size: Int
while (true) {
size = input.read(buf);
if (size != -1) {
output.write(buf, 0, size)
} else {
break;
}
}
output.flush()
}
}
}
}
}
Java代码：
byte[] buf = new byte[8192];
String name = "C:\\Users\\temp22\\Downloads\\2017-007-13\\china_gis_no_poly.db.xz";
try {
InputStream input = new FileInputStream(name);
FileOutputStream output= new FileOutputStream(name+".db");
try {
// Since XZInputStream does some buffering internally
// anyway, BufferedInputStream doesn't seem to be
// needed here to improve performance.
// in = new BufferedInputStream(in);
input = new XZInputStream(input);
int size;
while ((size = input.read(buf)) != -1)
output.write(buf, 0, size);
output.flush();
} finally {
// Close FileInputStream (directly or indirectly
// via XZInputStream, it doesn't matter).
input.close();
output.close();
}
} catch (FileNotFoundException e) {
System.err.println("XZDecDemo: Cannot open " + name + ": "
+ e.getMessage());
System.exit(1);
} catch (EOFException e) {
System.err.println("XZDecDemo: Unexpected end of input on "
+ name);
System.exit(1);
} catch (IOException e) {
System.err.println("XZDecDemo: Error decompressing from "
+ name + ": " + e.getMessage());
System.exit(1);
}